Many companies develop Resistive random-access memory (ReRAM) because ReRAM has advantages of low power consumption and high access speed.
Impedance of ReRAM is temperature dependent. Thus, if temperature varies, the impedance of ReRAM also varies. Usually, a resistor having constant resistance is used to generate the constant reference current. When temperature varies, the current output from ReRAM also varies. Thus, it is not easy to correctly determine whether ReRAM is in the high resistance state (HRS) or in the low resistance state (LRS). That is, it is not easy to determine whether data stored in ReRAM is logic 1 or logic 0.
Therefore, it is desirable to generate the reference current having temperature dependent. Even when temperature is varied in a wide range, it is easy to correctly determine whether ReRAM is in HRS or in LRS and to correctly determine data stored in ReRAM.